Apparatus for testing lubricating compounds



\JUUI ull llUUl Aug. 4, 1936. R. L. DO'AN APPARATUS FOR mswme wamcuxm courouuns Filed June 9, 1933 Patented Aug. 4, 1936 UNITED STATES uuui u" PATENT OFFICE APPARATUS FOR TESTING LUBRICATING COMPOUNDS Application June 9, 1933, Serial No. 675,029

6 Claims. (CI. 73-51) 10 emulsifying agent. In order to keep a tank of several thousands of gallons of this emulsion in a usable condition over a period of a year or more, it is necessary to pay considerable attention to such things as stability, fat content, and lubricat- 15 ing value, all of which are aii'ected by the chemical changes occurring in the compound as a result of usage.

Objects of the invention are to provide effective and efiicient apparatus for testing lubricatgo ing compounds.

In accordance with one embodiment of the invention, a measured retarding force is applied to an element and the retarding force is overcome by an opposing force applied by dynamic friction in the presence of a lubricating compound and the measured tension on the element at a point beyond the application of the friction is used in relation with the retarding force to determine the degree of friction and the lubricating value of the compound.

A complete understanding of the invention may be had by reference to the following description taken in conjunction with the accompanying drawing, in which '5 Fig. 1 is a side elevation of an apparatus embodying the invention;

Fig. 2 is a plan view of a wire drawing die and support; and

Fig. 3 is a sectional view taken on line 33 of 40 Fig. 2.

The invention will be described in connection with the testing of the lubricating value oi. wire drawing compounds. A suitable wire drawing compound which is sometimes used for drawing 45 copper wire may be made by compounding about 4.5 parts of fat consisting of tallow and rapeseed oil with about 0.5 parts of soap and about 95 parts of water. This compound is sometimes passed through a colloid mill to assist in the dis- 50 persion of the fat. In the copending application of R. P. Lutz relating to a method of making and controlling a lubricating compound, Serial No. 622,448, filed July 14, 1932, a method is disclosed by means of which the fat content and hydrogen 55 ion content of the compound may be controlled.

In addition to the control of these features, it is desirable in many instances to provide a further check on the suitability of the compound by determining the lubricating value of the compound to which this invention is directed. 5

Referring to the drawing, a reel 6 is shown having a supply of wire thereon, a strand 1 of which passes through a sleeve-like guide into a housing 9. In the housing the strand is passed around a capstan Ii and upwardly over an idler 10 or guide pulley I 2. The wire then passes through a die mounted in a die holder l3 in which its cross-section is reduced. In order to measure the tension applied to the strand in the die, the die holder I3 is mounted on a die block I4, which has a plurality of cylinders l5 and i6 therein. The two cylinders l5 are of the same diameter but of a larger diameter than the two cylinders IS. The cylinders I5 and 16 have pistons il therein which are provided with reduced portions 20 [8 at their upper ends which fit into apertures i 9 in die holder I3 to retain the die holder on the cylinders. The lower end of the cylinders are all interconnected by channels 2| which are filled with a suitable liquid, such as, for instance, oil. The channels are also connected to an outlet tube 22 which communicates with a pressure gage 23. In order to obtain a wider range of measurement of tension on the strand due to the die, various combinations of pistons i1 may be used. For instance, if a high tension is to be measured, all of the pistons may be used. If a lower tension is to be measured, the pistons in the cylinders l6 may be depressed and held in their depressed position by a plate 24 secured to the block i4 by screws 25 and only the pistons in cylinders i5 used. If a still lower tension is to be measured, the pistons in the cylinders l5 may be locked in their depressed position and only the pistons in the cylinders I6 used. The block l4 has a suitable aperture therein through which the strand passes over the capstan II and out of the casing through a sleeve-like guide 26.

The strand in leaving the casing passes under 5 an idler pulley 21, over a pulley 28, and under a pulley 29 to a takeup reel 3|. The pulley 28 is mounted on a rod 32 attached to a piston 33 in a cylinder 34, and this cylinder is connected by a tube 35 to a pressure gage 36. The gage 36 5 may be calibrated to indicate the tension in the strand between the idler pulley 21 and the capstan i I. The capstan I l is driven by a variable speed driving means 31 and the takeup reel is also driven by a variable speed driving means 38,

whereby the capstan and takeup reel may be driven independently at any selected speeds.

The lower portion of the casing 9 is partly filled with a lubricating compound which is continuously circulated by a pump M. The pump 4| is connected to the lower portion of the casing by a pipe 42 and an outlet tube 43 of the pump discharges the lubricant over the capstan II and the wires thereon.

The lubricating quality of the lubricant is determined by measuring the coefficient of friction between the wire and capstan. For this purpose the capstan H is rotated at such a speed that there will be slippage between all points of the Wire and the capstan; and the speed of the takeup reel 3| is adjusted to apply suflicient tension to the wire to cause it to be drawn through the die by the capstan. The coeflicient of dynamic friction at the capstan may be determined from the equation loge T1Zoge T2=21rRNu, where T1 is the force required to draw the wire through the die and is indicated by the gage 23; T2 is the force required to tighten the wire on the capstan, or in other words the tension on the strand after leaving the capstan, and is indicated by the gage 38; N is the number of turns around the capstan, and u is the coefficient of friction. This formula does not take into account the force required to bend the wire around the capstan. However, in the smaller sizes of wire, this is negligible and in the larger size it may be corrected for. It has been found that a chart may be drawn up by which the coefiicient of friction may be read on directly after observing the two gage readings.

One of the direct results of friction in the wire drawing process is the formation of copper dust, both in the dies and on the capstan, due to the abrasion on the wire. The copper dust settles in the bottom of casing 9 and may be recovered and freed from fat and moisture and weighed since it appears that the lubricating compound has a better lubricating quality when a minimum amount of copper dust is formed.

In practicing the invention, a sample of the lubricating compound in a wire drawing system is taken from time to time and its lubricating value is determined. If any deficiency is found in the lubricating value, steps are immediately taken to correct this condition. The invention is also of special value in determining the lubricating value of newly made or experimental com- Pounds.

While the invention has been described with particular reference to lubricating compounds for wire drawing, it will be understood that this is merely illustrative and that many changes and modifications may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. An apparatus for testing a lubricating compound, which comprises a die, a capstan for drawing a wire through the die, means for applying a lubricating compound to the wire, means for measuring the force applied to the die, means for tensioning the wire to cause it to frictionally engage the capstan, and means for measuring the tension required to engage the wire with the capstan.

2. An apparatus for testing a lubricating compound, which comprises a die, a capstan for drawing a Wire through the die, means for applying a lubricating compound to the capstan, means for measuring the force applied to the die, means for tensioning the wire to cause it to frictionally engage the capstan, and means for measuring the tension requiredto engage the wire with the gage for indicating the pressure exerted by said pistons, and means for at will rendering some of said pistons ineffective.

4. In a testing apparatus, a die, a block having a plurality of cylinders therein, arranged in diametrically opposed pairs, one pair of said cylinders being of a different size than another pair, pistons in said cylinders for movably supporting a die, means for measuring the pressure exerted on said pistons, and means for at will rendering some of said pistons ineffective.

5. An apparatus for testing a lubricating compound, comprising a die, a capstan for drawing a wire through the die, a block having a plurality of cylinders therein, pistons in said cylinders for supporting the die, means for measuring the pressure exerted on said pistons, means for tensioning the wire to cause it to frictionally engage the capstan, and means for measuring the tension applied by said tensioning means.

6. Test apparatus for the purpose described, comprising a movable element adapted to be subjected to a lubricating compound to be tested, means for imposing a measured load upon said element tending to resist movement thereof, means for applying a force to said element through dynamic frictional engagement therewith to maintain it in motion overcoming said resistance, means for applying pressure between said element and force applying means to provide a dynamic frictional engagement, and means for measuring the pressure factor necessary to eifect movement of said element.

RICHARD L. DOAN.

g :57 Certificate of Correction Patent No. 2,049,951. August 4, 1936.

RICHARD L. DOAN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 20, for the last half of the equation 21rRNu read 21r-Nu; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 27th day of October, A. D. 1936.

[SEAL] HENRY VAN ARSDALE,

Acting Commissioner of Patents. 

